Different methods for checking electronic data memories are known from the state of the art. A commonly used method is the cyclic redundancy check. In this method, in the simplest case, a signature is formed for each data block of a certain size and attached to the data block. The same method is applied anew on the data block including the attached signature. After this operation the result should be zero. If it deviates from zero, an error has occurred in the memory.
Such a test method can, however, only be applied if the content of the data block does not change during the test. Since the program for performing such a test is, most often, modularly constructed and requires memory capacity, it is necessary to exclude from the test the area currently used for memory. This is relatively complicated, fraught with risk and takes time for performing the test program. In order not to degrade the functional ability of the device, in which the memory element is applied, however, a test program should take as little time as possible.